In previous work (see Z01 ES 50044-02) designed to evaluate the reproductive and teratogenic effects of exposure to different noise spectra and temporal patterns, one of the spectra was associated with an increase in late stage fetolethality in the CF-1 mouse. This narrow band 18-20 kHz spectra, produced by a commercial device alleged to be aversive to rodents, was cycled on a one second rate from noon to midnight. In order to determine whether the effect was solely related to acoustic energy in the most sensitive auditory frequency band of the mouse (15-30 CHz) or to some other unknown factor, an experiment involving a band spanning 10-45 kHz was employed. Unfortunately CF-1 mice were no longer available to us; CD-1 mice were employed in this experiment.